1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
Unix SMB/CIFS implementation.
signal handling functions
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "system/wait.h"
/**
* @file
* @brief Signal handling
*/
/****************************************************************************
Catch child exits and reap the child zombie status.
****************************************************************************/
static void sig_cld(int signum)
{
while (waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0)
;
/*
* Turns out it's *really* important not to
* restore the signal handler here if we have real POSIX
* signal handling. If we do, then we get the signal re-delivered
* immediately - hey presto - instant loop ! JRA.
*/
#if !defined(HAVE_SIGACTION)
CatchSignal(SIGCLD, sig_cld);
#endif
}
/****************************************************************************
catch child exits - leave status;
****************************************************************************/
static void sig_cld_leave_status(int signum)
{
/*
* Turns out it's *really* important not to
* restore the signal handler here if we have real POSIX
* signal handling. If we do, then we get the signal re-delivered
* immediately - hey presto - instant loop ! JRA.
*/
#if !defined(HAVE_SIGACTION)
CatchSignal(SIGCLD, sig_cld_leave_status);
#endif
}
/**
Block sigs.
**/
void BlockSignals(bool block, int signum)
{
#ifdef HAVE_SIGPROCMASK
sigset_t set;
sigemptyset(&set);
sigaddset(&set,signum);
sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL);
#elif defined(HAVE_SIGBLOCK)
if (block) {
sigblock(sigmask(signum));
} else {
sigsetmask(siggetmask() & ~sigmask(signum));
}
#else
/* yikes! This platform can't block signals? */
static int done;
if (!done) {
DEBUG(0,("WARNING: No signal blocking available\n"));
done=1;
}
#endif
}
/**
Catch a signal. This should implement the following semantics:
1) The handler remains installed after being called.
2) The signal should be blocked during handler execution.
**/
void (*CatchSignal(int signum,void (*handler)(int )))(int)
{
#ifdef HAVE_SIGACTION
struct sigaction act;
struct sigaction oldact;
ZERO_STRUCT(act);
act.sa_handler = handler;
#ifdef SA_RESTART
/*
* We *want* SIGALRM to interrupt a system call.
*/
if(signum != SIGALRM)
act.sa_flags = SA_RESTART;
#endif
sigemptyset(&act.sa_mask);
sigaddset(&act.sa_mask,signum);
sigaction(signum,&act,&oldact);
return oldact.sa_handler;
#else /* !HAVE_SIGACTION */
/* FIXME: need to handle sigvec and systems with broken signal() */
return signal(signum, handler);
#endif
}
/**
Ignore SIGCLD via whatever means is necessary for this OS.
**/
void CatchChild(void)
{
CatchSignal(SIGCLD, sig_cld);
}
/**
Catch SIGCLD but leave the child around so it's status can be reaped.
**/
void CatchChildLeaveStatus(void)
{
CatchSignal(SIGCLD, sig_cld_leave_status);
}
|
